I am having the same issue all of a sudden. I can only use zoom with headphones in. Everything is updated on the computer and I have the most up-to-date zoom.
I can hear participants but they can't hear me. When I check audio settings the "test microphone" is grayed out. I've tested with other apps and websites and zoom is the only app with an issue.
@VJM817 if the Test Microphone is grayed out, it would indicate that Zoom thinks your headphones do not have a microphone. I have no idea why this would have just started happening, or why other software can see the microphone. I hate to suggest it, but have you rebooted your machine and/or restarted your headset (if it has independent power) lately?
